Antiemetics and Emetics

Emetic center of the brain is stimulated

Goal is to empty the GI tract of irritants and toxins

Symptoms not a disease

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Nausea and Vomiting

Causes are varied - motion sickness - morning sickness - intense pain - chemical toxins - emotional stress

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Nausea and Vomiting

Usually harmless but can signal a serious condition

- increased intracranial pressure - concussions - encephalitis - meningitis - intestinal blockage - appendicitis - migraine headaches - brain tumors

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Nausea and Vomiting

Risk for aspirationRisk for dehydration or electrolyte imbalances

Children, the elderly, and those with chronic illnesses are more at risk of complications

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Concerns

Agents that induce vomiting◦Used in overdoses

Example◦Ipecac syrup

Inappropriate use◦Clients with bulimia

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Emetics

Five categories of antiemetics1.Anticholinergics 2.Antihistamines 3.Neuroleptic agents4.Prokinetic agents5.Serotonin blockers

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Antiemetics

Anticholinergics◦Bind to and block acetylcholine receptors Prevent nausea stimuli from

being transmitted Scopolamine patch – motion

sickness prevention

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Anticholinergics and Antihistamines

Antihistamines◦Block histamine (H2) receptors

Prevent cholinergic stimulation Antivert for motion sickness,

vertigo Promethazine (Phenergan) for

nausea/emesis Use caution with IV route

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Anticholinergics and Antihistamines

Dry mouthUrinary retentionBlurred vision, dizzinessUse with caution in patients with benign prostatic hypertrophy and narrow-angle glaucoma

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Side Effects of Antihistamines and Anticholinergics

Neuroleptic agents◦Bind to the dopamine receptors and block action Limit dopamine activity

Prokinetic agents◦Block dopamine◦Stimulate acetylcholine to increase gastric emptying

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Neuroleptic and Prokinetic Agents

Zofran Block serotonin receptors in the gastrointestinal tract

Block serotonin receptors in the central nervous system (emetic center)◦Used often when antineoplastic agents are being given

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Serotonin Blockers

Prevents transmission of afferent visceral and chemoreceptor triggers

Most common agents for patients on chemotherapy

Also used for patients with migraines, gastroenteritis, and postoperatively

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Serotonin Blockers

Evaluate effectiveness of therapy

If inducing vomiting, main goal is determination of toxic agent to determine if vomiting is appropriate and other treatment needs

Ensure an adequate airway

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Nursing Considerations

Prevention is better than cure – anticipate when possible

Assess patient for reason behind nausea/vomiting

Prevent aspiration

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Nursing Considerations